Re: 3D medical modelling

From: Andrew Layton (
Date: Mon Mar 11 2002 - 18:48:07 EET

There is work being done in this area by Shayne Kondor of the Georgia Tech
Research Institute.

His e-mail is

At 10:53 AM 3/10/2002 , wrote:

>I usually just read this list but couldn't resist putting my 2 cents worth in
>on the application of r-p in medicine. In my opinion, there is no question
>that the technology is available to transform the way we diagnosis and treat
>patients but the problem is more complex than just the technology. I would
>like to use a simple example that most of you can relate to. If your son or
>daughter went to the orthodontist to have his or her teeth straightened or
>face changed with skeletal surgery some very specific evaluations would be
>preformed. The following information is generally needed: photos of the face,
>two large x-rays of the head, models of the teeth and records of the way the
>TMJ (joints ) relate the jaws and teeth to each other. None of this
>information is digital (except possibly the photo) much of the process of
>making a diagnosis is done with a pencil on a sheet of acetate over the
>x-rays. This is a very scientific process and used by virtually all surgeons
>and orthodontists. Tracings are made of the bones of the face and teeth and
>their spatial relationship to each other measured and compared to known
>standards. Other measurements are made of the models and if jaw surgery is
>needed, acetate templates are cut of the tracings to rotate and move the
>teeth and bone in 2D (on the desk top) to determine the final result. If a
>surgeon is planning to move the jaws by cutting them and repositioning them
>in a new relationship, he usually mounts the models in an metal instrument
>that is like the jaws and cuts the plaster models to make the planned moves
>to see the final result before surgery. If the result is acceptable,
>autopolymerizing acrylic resin templates are made of the teeth to relate them
>together during surgery. This is accomplished using the TMJ (joints) as an
>axis of rotation and recording the number of degrees of rotation or opening
>to precisely position the cut jaw before plating it in place with titanium
>plates and screws.
>This is only a part of the process but I think it helps illustrate the
>present state of affairs. Now as you all know we could get a CT scan of the
>patient and have better information about the real soft and hard tissue
>anatomy of the patient, and we could scan the teeth or models of the teeth
>many ways and relate that scan date to the CT data. We could also record jaw
>movement digitally and allow for the scan data of the teeth and bones to be
>moved in CAD to the new desired position and we could make the surgical
>templates for positioning the teeth with r-p. None of these processes is a
>big deal and can be done easily. So why isn't everyone doing it?
>The answer to that question is the critical point. Oral and maxillofacial
>surgeons, orthodontists, plastic surgeons, neurosurgeons and a host of other
>people would love to have scanning, CAD and r-p do the jobs they presently do
>by hand but it will not happen until software is developed that does what
>they need easily and in a fashion that is similar to the present process.
>That will only happen when we create inter-relationships that allow
>engineers, surgeons, clinicians, researchers and marketing people to work
>together to develop the software we need.
>Generally, just providing conventional CAD and scanning equipment will not
>work. Most medical people are very busy, they do not have the time to learn
>Pro-e, they need someone else to do that for them.
>For more information about the rp-ml, see

Andrew C. Layton
Program Manager, Rapid Prototyping & Manufacturing Institute
Georgia Institute of Technology
813 Ferst Dr. N.W., Atlanta, GA 30332-0560
Phone: (404) 385-1053 Fax: (404) 894-0957

For more information about the rp-ml, see

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